<template>
  <div class="spec-preview" v-if="skuImageList" >
    <img :src="skuImageList[index].imgUrl" />
    <div class="event" @mousemove="fbigimg"></div>
    <div class="big" v-if="skuImageList">
      <img :src="skuImageList[index].imgUrl" ref="big" />
    </div>
    <div class="mask" ref="mask"></div>
  </div>
</template>

<script>
import {ref} from 'vue'
import Bus from '@/bus.js'
  export default {
    name: "Zoom",
    props:['skuImageList'],
    setup(props) {
      let index=ref(0)  
    Bus.on('showimg',(n)=>{
          index.value=n
    })
      return{index}
    },
    // 由于vue3.x获取dom元素节点不方便
    // 放大镜功能用vue2编写
    methods: {
      fbigimg(event){
       let mask=this.$refs.mask
       let big=this.$refs.big
       let left = event.offsetX-mask.offsetWidth/2
       let top = event.offsetY-mask.offsetHeight/2
      //  约束范围
      if(left<=0) left=0
      if(left>=mask.offsetWidth) left=mask.offsetWidth
       if(top<=0) top=0
      if(top>=mask.offsetWidth) top=mask.offsetWidth
      // 修改mask的left|top值
      mask.style.left=left+'px'
      mask.style.top=top+'px'
      big.style.left=-2*left+'px'
      big.style.top=-2*top+'px'
      }
    },
  }
</script>

<style lang="less">
  .spec-preview {
    position: relative;
    width: 400px;
    height: 400px;
    border: 1px solid #ccc;

    img {
      width: 100%;
      height: 100%;
    }

    .event {
      width: 100%;
      height: 100%;
      position: absolute;
      top: 0;
      left: 0;
      z-index: 998;
    }

    .mask {
      width: 50%;
      height: 50%;
      background-color: rgba(0, 255, 0, 0.3);
      position: absolute;
      left: 0;
      top: 0;
      display: none;
    }

    .big {
      width: 100%;
      height: 100%;
      position: absolute;
      top: -1px;
      left: 100%;
      border: 1px solid #aaa;
      overflow: hidden;
      z-index: 998;
      display: none;
      background: white;

      img {
        width: 200%;
        max-width: 200%;
        height: 200%;
        position: absolute;
        left: 0;
        top: 0;
      }
    }

    .event:hover~.mask,
    .event:hover~.big {
      display: block;
    }
  }
</style>